60 lines
1.6 KiB
Go
60 lines
1.6 KiB
Go
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package builder
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import (
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"reflect"
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"sync"
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)
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var (
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registry = make(map[reflect.Type]reflect.Type)
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registryMux sync.RWMutex
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)
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// RegisterType maps the given builderType to a structType.
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// This mapping affects the type of slices returned by Get and is required for
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// GetStruct to work.
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//
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// Returns a Value containing an empty instance of the registered builderType.
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//
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// RegisterType will panic if builderType's underlying type is not Builder or
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// if structType's Kind is not Struct.
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func RegisterType(builderType reflect.Type, structType reflect.Type) *reflect.Value {
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registryMux.Lock()
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defer registryMux.Unlock()
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structType.NumField() // Panic if structType is not a struct
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registry[builderType] = structType
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emptyValue := emptyBuilderValue.Convert(builderType)
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return &emptyValue
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}
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// Register wraps RegisterType, taking instances instead of Types.
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//
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// Returns an empty instance of the registered builder type which can be used
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// as the initial value for builder expressions. See example.
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func Register(builderProto, structProto interface{}) interface{} {
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empty := RegisterType(
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reflect.TypeOf(builderProto),
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reflect.TypeOf(structProto),
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).Interface()
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return empty
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}
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func getBuilderStructType(builderType reflect.Type) *reflect.Type {
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registryMux.RLock()
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defer registryMux.RUnlock()
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structType, ok := registry[builderType]
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if !ok {
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return nil
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}
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return &structType
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}
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func newBuilderStruct(builderType reflect.Type) *reflect.Value {
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structType := getBuilderStructType(builderType)
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if structType == nil {
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return nil
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}
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newStruct := reflect.New(*structType).Elem()
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return &newStruct
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}
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